What happened
On December 6, 2006, at approximately 16:30 local time, a Bell 204B helicopter, registration OB-1833-P, was performing a scheduled flight from helipad PS #03 to Ayacucho, Peru. The aircraft, operated by Servicios Aéreos de Los Andes S.A.C., was transporting a group of passengers, including representatives from the World Bank, as part of operations for the Camisea gas pipeline.
During the initial climb to a planned altitude of 14,200 feet, the pilot encountered challenging meteorological conditions. While flying approximately five miles from the departure point, the pilot observed that the right side of the valley was obscured by Altostratus clouds. To avoid a mountain peak standing at 14,000 feet, the pilot attempted to maneuver to the left side of the valley. During this maneuver, the pilot initiated a right turn to return to the departure point, at which point the aircraft struck a mountainside at an altitude of 13,700 feet. The impact caused the right skid to break, leading to a loss of control and subsequent damage to the rotor blades and tail boom.
The investigation
The CIAA investigation examined the flight path, the meteorological conditions at the time of the accident, and the operational environment. Investigators reviewed the aircraft's maintenance records, which showed the engine and rotor components were within their service limits. The investigation also looked into the crew's decision-making process and the external pressures present during the mission.
Findings
- The primary cause of the accident was impact with terrain following a loss of control, driven by mountain gusty winds and marginal visibility that degraded the aircraft's climb performance.
- The pilot's evaluation of the deteriorating weather conditions was insufficient for the required flight path.
- There was evidence of pressure exerted by a representative of the contracting company to proceed with the flight despite the poor weather.
- Operational risks were increased by the lack of certified weather observers at the remote gas pipeline helipads and the absence of specific flight route guides for the PS #03 to Ayacucho sector.
- The aircraft suffered major damage to the airframe, including the rotor blades, mast, and tail boom, though all 9 occupants survived the crash without injury.